HIV screening : Method of Serum Preparation
HIV screening : Method of Serum Preparation… In this brief publication, we are going to explain extensively on the following topics:
- Examination of blood for HIV screening
- Thin film preparation
- Thick blood film preparation in HIV screening
- Microscopy in HIV screening
Exactly 2ml of blood sample was collected from patient and introduced into sterile dry tube and was allowed to clot and refract which it 1 centrifuged at 3500 rpm for 5 minutes to give clear sera which was stored at 20oc and analyzed within 2-3 days of collection (Nwuzo et al., 2009).
Examination of blood for HIV screening: The HIV status of the patients was determined by enzyme linked immunosorbent assay (ELISA) method using commercial available ELIS kits: ACON Diagnostics, USA, Biosystem, USA) and was confirmed by a second stage confirmatory test of two to three rapid tests with different principles (Capillus HIV ½ Assay, Trinity biotech, Ireland and Determines kits, Japan Co. LTD) of antibodies and antigen methods as recommended by WHO for low resource countries including Nigeria (CDC, 2004).
Microscopy in HIV screening
Thin film preparation: A drop of flesh blood was gently made to touch one end of a clean grease free slide. A spreader was used to spread the blood along the glass slide.
The spreader was held at suitable angle 45 and pushed the spreader along side, drew smeared forming a thin film. The thin film was allowed to air dry, then fixed with three drops of methanol which helps in proper HIV screening.
The stain was allowed to stain for 30-45 minutes out of sunlight. Clean water was poured gently on the surface of glass slide was gently poured off. The forceps was used to remove the slide and placed it on the slide cleaned and examined with a microscope.
Thick blood film preparation in HIV screening : A fresh drop of blood was gently touched onto the center of a clean grease free slide.
A beveled piece of glass (spreader) a little narrower than the slide was used to spread a drop of blood in a circular form. The thick film was allowed to air dry thoroughly; it was not fixed so as to permit dehaemoglobinization. The forceps was used to place the slide on a staining trough.
Three percent (3%) Giemsa solution was prepared in buffer or distilled water in sufficient quantity to fill the number of staining trough. The stain was poured gently into the staining trough, until all the slides were completely covered.
The stain was allowed to dry for 30-45minutes. Clean water was poured gently on the surface to remove staining solution deposit. The remaining water on the surface of the glass slide was gently poured off.